Is this a transducer, or display head (ST60 Tri-Data) problem?

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum sailjumanji,

As you have suggested the depth instrument may continue to function when its LCD is exhibiting signs of failure. Typically instrument depth instruments will support repeating depth when operating in depths ranging from 3' to 200' below the transducer. Accordingly, when operating in the offshore depths specified, loss of bottom would not be unexpected. However, as you have pointed out, the problem should abate when the vessel is operating in shallower waters. It is recommended that troubleshooting begin with inspection of the transducer's cable to ensure that it is undamaged, that the wire connections to the 1/8" female blade connectors are in good condition, and that the instruments 1/8" male blade pins are free of corrosion. If so, then troubleshooting the problem would involve testing the instrument with another transducer which was known to be operational. The test transducer would either be suspended over the side of the placed atop a Zipper Locking plastic bag which has been completely filled with water and placed inside on the bottom of the hull (hull must be constructed of solid fiberglass (i.e. core materials not used). After duplicating the problem, then the test transducer would be connected to the instrument. Should the problem abate, then the transducers would need to be replace. Should the problem persist, then the instrument should be replaced with an i50 Depth or i50 Tridata Instrument.